Opioid use and healthcare costs among patients with DPNP initiating duloxetine versus other treatments

A review of the clinical utility of duloxetine in the treatment of diabetic peripheral neuropathic pain

Diabetes mellitus is a world-wide epidemic with many long-term complications, with neuropathy being the most common. In particular, diabetic peripheral neuropathic pain (DPNP), can be one of the most distressing complications associated with diabetes, leading to decreases in physical and mental quality of life. Despite the availability of many efficient medications, DPNP remains a challenge to treat, and the optimal sequencing of pharmacotherapy remains unknown. Currently, there are only three medications approved by the US Food and Drug Administration specifically for the management of DPNP. Duloxetine (DUL), a selective serotonin-norepinephrine reuptake inhibitor, is one of these. With the goal of optimizing pharmacotherapy use in DPNP population, a review of current literature was conducted, and the clinical utility of DUL described. Along with early clinical trials, recently published observational studies and pharmacoeconomic models may be useful in guiding decision making by clinicians and managed care organizations. In real-world practice settings, DUL is associated with decreased or similar opioid utilization, increased medication adherence, and similar health care costs compared with current standard of care. DUL has consistently been found to be a cost-effective option over short time-horizons. Currently, the long-term cost-effectiveness of DUL is unknown. Evidence derived from randomized clinical trials, real-world observations, and economic models support the use of DUL as a first-line treatment option from the perspective of the patient, clinician, and managed care payer.

Real-world treatment patterns and opioid use in chronic low back pain patients initiating duloxetine versus standard of care

To describe the use of pain medications in patients with chronic low back pain (CLBP) after initiating duloxetine or standard of care (SOC [muscle relaxants, gabapentin, pregabalin, venlafaxine, and tricyclic antidepressants]) for pain management, pharmacy and medical claims from Surveillance Data, Inc (SDI) Health were analyzed. Adult patients with CLBP who initiated duloxetine or SOC between November 2010 and April 2011 were identified. Treatment initiation was defined as no pill coverage for duloxetine or SOC in the previous 90 days. Included patients had no opioid use in the 90 days before initiation. Propensity score matching was used to select patients with similar baseline demographic and clinical characteristics for duloxetine and SOC cohorts. Compliance with index medication was assessed via medication possession ratio (MPR) and proportion of days covered (PDC) for 6 months after initiation. The proportion of patients receiving opioids and days on opioids after index date were assessed, and regression models were estimated to compare opioid use between cohorts. A total of 766 patients initiated duloxetine and 6,206 patients initiated SOC. After matching, 743 patients were selected for the duloxetine (mean age 57 years; female 74%) and SOC (mean age 57 years; female 75%) cohorts, respectively. Of the duloxetine cohort, 92% started on or below recommended daily dose (≤60 mg). The duloxetine cohort had significantly higher MPR (0.78 versus [vs] 0.60) and PDC (0.50 vs 0.31), were less likely to use opioids (45% vs 61%), and had fewer days on opioids (median 0 vs 7 days) than the SOC cohort (all P < 0.001). After adjusting for demographic and clinical characteristics, the duloxetine cohort initiated opioids later than the SOC cohort (hazard ratio 0.77, 95% confidence interval 0.66–0.89). CLBP patients initiating duloxetine had better compliance with initiated medication and were less likely to use opioids than those initiating SOC.

Relative contributions of norepinephrine and serotonin transporters to antinociceptive synergy between monoamine reuptake inhibitors and morphine in the rat formalin model

Multimodal analgesia is designed to optimize pain relief by coadministering drugs with distinct mechanisms of action or by combining multiple pharmacologies within a single molecule. In clinical settings, combinations of monoamine reuptake inhibitors and opioid receptor agonists have been explored and one currently available analgesic, tapentadol, functions as both a µ-opioid receptor agonist and a norepinephrine transporter inhibitor. However, it is unclear whether the combination of selective norepinephrine reuptake inhibition and µ-receptor agonism achieves an optimal antinociceptive synergy. In this study, we assessed the pharmacodynamic interactions between morphine and monoamine reuptake inhibitors that possess different affinities and selectivities for norepinephrine and serotonin transporters. Using the rat formalin model, in conjunction with measurements of ex vivo transporter occupancy, we show that neither the norepinephrine-selective inhibitor, esreboxetine, nor the serotonin-selective reuptake inhibitor, fluoxetine, produce antinociceptive synergy with morphine. Atomoxetine, a monoamine reuptake inhibitor that achieves higher levels of norepinephrine than serotonin transporter occupancy, exhibited robust antinociceptive synergy with morphine. Similarly, a fixed-dose combination of esreboxetine and fluoxetine which achieves comparable levels of transporter occupancy potentiated the antinociceptive response to morphine. By contrast, duloxetine, a monoamine reuptake inhibitor that achieves higher serotonin than norepinephrine transporter occupancy, failed to potentiate the antinociceptive response to morphine. However, when duloxetine was coadministered with the 5-HT₃ receptor antagonist, ondansetron, potentiation of the antinociceptive response to morphine was revealed. These results support the notion that inhibition of both serotonin and norepinephrine transporters is required for monoamine reuptake inhibitor and opioid-mediated antinociceptive synergy; yet, excess serotonin, acting via 5-HT₃ receptors, may reduce the potential for synergistic interactions. Thus, in the rat formalin model, the balance between norepinephrine and serotonin transporter inhibition influences the degree of antinociceptive synergy observed between monoamine reuptake inhibitors and morphine.

Applying standardized drug terminologies to observational healthcare databases: a case study on opioid exposure

Observational healthcare databases represent a valuable resource for health economics, outcomes research, quality of care, drug safety, epidemiology and comparative effectiveness research. The methods used to identify a population for study in an observational healthcare database with the desired drug exposures of interest are complex and not consistent nor apparent in the published literature. Our research evaluates three drug classification systems and their impact on prevalence in the analysis of observational healthcare databases using opioids as a case in point. The standard terminologies compiled in the Observational Medical Outcomes Partnership’s Common Data Model vocabulary were used to facilitate the identification of populations with opioid exposures. This study analyzed three distinct observational healthcare databases and identified patients with at least one exposure to an opioid as defined by drug codes derived through the application of three classification systems. Opioid code sets were created for each of the three classification systems and the number of identified codes was summarized. We estimated the prevalence of opioid exposure in three observational healthcare databases using the three defined code sets. In addition we compared the number of drug codes and distinct ingredients that were identified using these classification systems. We found substantial variation in the prevalence of opioid exposure identified using an individual classification system versus a composite method using multiple classification systems. To ensure transparent and reproducible research publications should include a description of the process used to develop code sets and the complete code set used in studies.

Opioids before and after initiation of pregabalin in patients with diabetic peripheral neuropathy

OBJECTIVES

To examine opioid prescription claims before and after initiation of pregabalin in patients with a diagnosis of diabetic peripheral neuropathy (DPN).

METHODS

This retrospective analysis used a national commercial database of integrated inpatient, outpatient, and prescription claims to identify adults with a DPN diagnosis code within 360 days prior to the first claim for pregabalin between January 1, 2006 and March 31, 2008. Prescription claims for pregabalin or opioids were analyzed in nine consecutive 60-day periods from 180 days before through 360 days after the first pregabalin claim. It was not possible to establish drug administration dates, compliance rates, indications for opioid use, or reasons for treatment discontinuation.

RESULTS

Of the 8004 adults who met eligibility criteria, 6080 (76%) received an opioid within the 180 days before and/or 360 days after their first prescription for pregabalin, including 3956 (49%) both before and after, 1580 (20%) after only, and 544 (7%) before only. The percentage of patients with pregabalin claims covering ≥20 of 60 days (within 60-day periods) was 99% (day 1-60), 63% (day 61-120), 50% (day 121-180), 45% (day 181-240), 42% (day 241-300), and 39% (day 301-360). The percentage of patients with opioid claims covering ≥20 of 60 days within the 60-day periods remained stable (range, 25-30%). Among patients with opioid claims, 73-76% received only short-acting opioids, 6-7% received only long-acting opioids, and 18-20% received both short- and long-acting opioids. In the first year, 982 (12%) patients had opioid claims covering ≥20 of 60 days in every 60-day period (i.e., persistent use of opioids). Coexisting musculoskeletal (95%) or neuropathic (61%) pain conditions were frequent.

CONCLUSION

A majority of patients with DPN receive an opioid before and/or after their first pregabalin claim. Pregabalin neither interferes with nor replaces opioid use for pain management in patients with DPN. Although nearly 1 in 8 patients received opioids throughout the study period, most claims were for short-acting opioids. The majority of this DPN sample had other pain conditions, including musculoskeletal and neuropathic pain conditions. These results highlight the frequency of opioid use with pregabalin, particularly short-acting opioids.